The money comes to the Presidio in a roundabout manner. It's part of a $2.4 billion bond issue for expansion of San Francisco International Airport. Part of the expansion means paving over about 17 acres of marsh near the airport, and under environmental law, the city is required to replace what it plans to destroy, a process called mitigation.

Instead of a project on the Peninsula, Airports Director John Martin picked the Crissy Field marsh, a site where the Park Service hopes to restore a 20-acre salt marsh that was paved over in 1915 for the Panama-Pacific International Exposition.

Later, it was used for an Army airfield and for barracks, shops, offices and parking lots.

The Park Service wants to rip up the asphalt put in by the U.S. Army over the years and put in not only the original salt marsh, but grasslands, sand dunes and a picnic area, about 100 acres in all.

"A window on the bay" is what Representative Nancy Pelosi, D- San Francisco, called it. She is a major advocate for the Presidio and was on hand for the announcement at the site yesterday.

The money for the Crissy Field project -- about $16 million in all -- will be privately raised by the nonprofit Golden Gate National Parks Association. San Francisco's is the first major contribution to the project.

Close to 90 percent of the marshlands that existed around San Francisco Bay have been filled in for various developments. Restoration of the Crissy Field marsh, which is very near the Golden Gate, marks the first time a wetlands area that has been destroyed will have been restored.

Robert Chandler, who manages the Presidio for the National Park Service, said the restored marsh would be "a signature piece" for the Presidio and a valuable educational tool for children and adults.

A plan for the project was approved by the Golden Gate National Recreation Area advisory committee last month. If the rest of the money is raised, the project could be completed by early 1999, the park service said.